Observation of soliton propagation dynamics using a novel time-resolved spectral reflectometer

We have developed a simple and reliable method that uses backscattered light for observing the spectral evolution of solitons and other nonlinear pulses and does not disturb the optical fiber. Here we present measurements of the spectral evolution of 8 ps solitons in a 5 km length of fiber, and compare them with numerical soliton propagation results. Our results show that the details of the soliton´s spectral evolution, especially when higher-order solitons are involved, are sensitive to both the initial launched pulse shape and its chirp. Future experimental studies using our method should reveal much more about the characteristics of nonlinear pulse propagation in fiber. Also, it should make it feasible to measure fiber characteristics such as nonlinearity, variation in mode diameter, and other parameters that affect or are affected by pulse intensity.